Click chemistry towards thermally reversible photochromic 4,5-bisthiazolyl-1,2,3-triazoles

• Chenxia Zhang,
• Kaori Morinaka,
• Mahmut Kose,
• Takashi Ubukata and
• Yasushi Yokoyama

Beilstein J. Org. Chem. 2019, 15, 2161–2169, doi:10.3762/bjoc.15.213

• thus prepared, which belong to the terarylene family, showed thermally reversible photochromism. The absorption maximum wavelengths of the closed forms are longer than other terarylenes reported so far. The thermal back reactions are much faster when the substituents on the terminal phenyl groups are

• electron-withdrawing cyano groups than when they are electron-donating methoxy groups. Keywords: aromatic stabilization energy; diarylethene; ruthenium(I) catalysed Huisgen cyclization; terarylene; thermally reversible photochromism; Introduction Diarylethenes are one of the most widely investigated

• “click” reaction. They showed thermally reversible photochromism in various solvents. The absorption maximum wavelengths of 1c (with unsubstituted peripheral phenyl groups) and 2c (with methoxy groups on the phenyl groups) are close to 700 nm, while that of 3c (with cyano groups on the phenyl groups) was